Potential to rectify immune system after Caesarean
Responding to the study, Professor Neil Mabbott, personal chair in immunopathology at the Roslin Institute of the University of Edinburgh, told the Science Media Centre: “This is a very interesting and important study. The authors show that infants delivered by a vaginal birth had higher responses to the two different types of vaccines against bacterial diseases, and this was associated with higher abundances of the potentially beneficial bacteria known as Bifidobacterium and E. coli in their intestines.”
He added: “This study raises the possibility that it may be possible to treat infants, especially Caesarean-delivered infants, with a bacterial supplement, or even a product produced by these beneficial bacteria, to help improve their immune systems, enhance their responses to certain vaccines and reduce their susceptibility to infections.”
The study raises important questions, he said, including whether the increased antibody levels from pneumococcal and meningococcal vaccinations following vaginal birth also leads to increased protection of the infants against infection or serious disease.
Sheena Cruickshank, immunologist and professor in biomedical sciences at the University of Manchester, England, commented: “It is now well established that the microbiome is important in immune development. In turn the mode of delivery and initial method of feeding is important in how the microbiome is first seeded in the baby.”
“However, other factors such as exposure to antibiotics and subsequent diet also play a role in how it then develops, making understanding the way the microbiome develops and changes quite complex. Microbes works as communities, and it can be difficult to determine whether changes in single species are important functionally. Breast milk also plays an important role in protecting the baby via transfer of maternal immunoglobulins, which will wane over a period of 6-12 months in the baby – thus ascertaining whether it’s the baby’s Ig is challenging.
“Given the complexity of the multitude of interactions, it is important that this is accounted for, and group sizes are large enough to ensure data is robust. Whilst this is an interesting study that adds to our knowledge of how the microbiome develops and the possible implications for immune development, it is still very preliminary, and the small group sizes warrant a need for further studies to verify this in larger groups.”
She added: “We will need to understand whether possible impacts of maternal delivery and feeding on immune development or vaccine responses can be restored by, for example, manipulating the microbiome.”
Professor Kim Barrett, vice dean for research at the University of California, Davis School of Medicine, said that, while further research was needed to uncover if and how manipulation of the human microbiome following C-section births might improve vaccine efficacy, “the work should at least lead to prompt additional consideration about an unintended consequence of the ever-increasing use of C-sections that may not be medically-necessary.”
Dr. Marie Lewis, researcher in gut microbiota at the University of Reading, England, said: “We have known for quite some time that the mode of delivery is incredibly important when it comes to the type of bacteria which colonize our guts. We also know that our gut bacteria in early life drive the development of our immune system, and natural births are linked with reduced risks of developing inflammatory conditions, such as asthma. It is therefore perhaps not really surprising that mode of delivery is also linked to responses to vaccinations.”
“The really interesting part here is the extent to which our gut microbiotas are accessible and changeable, and this important work could pave the way for administration of probiotics and prebiotics to improve vaccine responses in Caesarean-born children.”